Web Apps on a Pedestal

Learn how to build web applications in Clojure using the Pedestal library.

http://github.com/rkneufeld/pedestal-workshop

Transcript

1. Web Apps on a Pedestal
2. @rkneufeld – rkn.io Ryan Neufeld
5. Pedestal > Ring
6. Nailed Down
7. Flying Free
8. Enter the workshop
9. Todo-it
10. Demo project-building time
11. [“/hello” {:get hello-world}] ! Handler map Path pattern Anatomy Lesson: Routes
12. [“/hello” {:get hello-world} child-routes…] Anatomy Lesson: Children [“/“ [“/hello” {:get hello-world}]]
13. [[[“/“ [“/hello” {:get hello-world}]]]] Why so nested?
14. [[context routes…]] ! “hello” route App name, port, host Anatomy Lesson: Context
15. [[:public “example.com” routes…] [:api “api.example.com” routes…]] Anatomy Lesson: Contexts
16. Demo project-building time part ii
17. Exercise #1 1. Install Leiningen (http:/ /leiningen.org/#install) 2. git clone https:/ /github.com/rkneufeld/pedestal-workshop 3. Checkout exercise-1 4. Run the app w/ lein run 5. Visit localhost:8080/hello 6. Change “Hello, World!” to “Hello, <your name>!”* *You’ll need to restart the server
18. Demo routes & interceptors
19. No Handler is an Island
20. It takes a village* *Of middleware and handlers OK, doesn’t have the same ring to it… Enter from left to right Leave from right to left
21. Anatomy Lesson: Interceptors
22. Anatomy Lesson: Interceptors
23. Anatomy Lesson: Interceptors
24. Routers are Interceptors
25. Where they live (def service {::http/interceptors [… (router routes)]…} Before or after routing
26. [[[“/” ^:interceptors […] [“/hello” {:get hello-world] [“/goodbye” …]]] Where they live Inside routes
27. [[[“/“ [“/hello” {:get hello-world] [“/goodbye” …]]] Where they live Inside routes * * *Attachment points *
28. Demo routes & interceptors
29. Exercise #2 1. Checkout exercise-2 2. Restart your server w/ lein run 3. Visit localhost:8080/hello?name=<yours name> 4. Use the (or x y) form to provide "World" as a default name if none is provided. 5. Bonus: Write a defon-response interceptor that changes :header’s "Server" key to something unique of your choosing.
30. A little persistence
31. A little persistence
32. MVC* CRUD
33. MVC* CRUD
34. Demo A lil’ persistence
35. Exercise #4 1. Checkout exercise-4 2. Launch a REPL w/ lein repl 3. Require and enter todoit.todo.db • (require 'todoit.todo.db) • (in-ns 'todoit.todo.db) 4. Create, Read, Update, then Destroy a TODO • Get a db value with (d/db conn) 5. Bonus: Write a query completed-todos that ensures [?id :todo/completed? true]
36. Demo Wiring up C & R
37. Exercise #5 1. Checkout exercise-5 2. Try out /todos 3. Implement and wire-up a create function in todo.clj Hint: Use let à la hello-world to extract [:form-params “title”] and [:form-params “description”]. Once you’ve created a TODO, redirect to (url-for :todos).
38. New Paint Job
39. Demo New Paint Job
40. Hiccup [:tag {attributes} children] required optional optional .class #id optional
41. Hiccup <h1>The Title</h1> ! <div class=“foo”> <p>Great content</p> </div> ! <form action=“/todos” method=“post”> <input name=“title” /> </form> [:h1 “The Title”] ! [:div.foo [:p “Great Content”]] ! ! [:form {:action “/todos” :method “post”} [:input {:name “title”}]
42. Demo New Paint Job
43. Exercise #6 1. Checkout exercise-6 2. Try out the new /todos 3. Add a TODO without a title. Oops! 4. Modify the TODO form’s title to be required (hint, the required attribute).
44. Demo Update & Destroy
45. Exercise #7 1. Checkout exercise-7 2. Try out toggling and deleting TODOs 3. Create a delete-all action. You’ll need a: • Route, • Handler, • Model Action, and • Form
46. Questions? bit.ly/pedestal-ws @rkneufeld Photo credits: https:/ /flic.kr/p/bE6KtD, https:/ /flic.kr/p/9p4utz pedestal.io